Hanging petunias or mini petunias love to hang down. Any pots on a stump, a pedastal, or even bricks or corner of the porch will support your pot or the flowers. You are on the path of a great idea! If it were me, I would look in the nurseries or department stores that sell the and see what they have done to "advertise" them and see what you like and what will be pretty in your yard.